P1606: PRIMARY AND SECONDARY IMMUNE THROMBOCYTOPENIA (ITP) IN ADULTS: REAL WORLD COMPARATIVE RETROSPECTIVE STUDY FROM THE ITP REGISTRY OF THE HELLENIC SOCIETY OF HEMATOLOGY
Authors: Emily Stavroulaki, Charalampos Pontikoglou, Theodora Chatzilygeroudi, Alexandra Kouraklis-Symeonidis, Argiris Symeonidis, Maria Dimou, Panayiotis Panayiotidis, Giorgos Drakos, Aspasia Koudouna, Athanasios Galanopoulos, Vasileia Kaliafentaki, Angelos Matheakakis, Christina Lekarakou, Peggy Kanellou, Eleni Gavriilaki, Syrigou Antonia, Ioanna Sakellari, Dimitra Liapi, Georgios Tsirakis, Anna Kolovou, Sofia Chatzileontiadou, Maria Papaioannou, Aikaterini Souravla, Maria Dellatola, Maria Pagoni, Maria Bobola, Panagiotis Diamantopoulos, Marina Mantzourani, Nora-Athina Viniou, Aikaterini Megalakaki, Ioanna Christodoulou, Efthymia Vlachaki, Stavroula Giannouli, Vasiliki Gkalea, Charis Matsouka, Ioannis Kotsianidis, George Vassilopoulos, Maria Protopappa, Eleftheria Hatzimichael, Panagiotis Zikos, Marianna Politou, George N Chalkiadakis, Helen Papadaki
Journal: HemaSphere (2023)

Topic: 32. Platelet disorders Background: ITP can be classified as primary or secondary based on the absence or presence of other causes or disorders associated with thrombocytopenia. Although these forms of ITP have been traditionally considered as distinct disease entities, comparative studies are rare and the differences and similarities between primary and secondary ITP have not been adequately elucidated thus far. Aims: To comparatively describe real world characteristics at diagnosis and evaluate disease outcome in patients with primary (Group-1) and secondary ITP (Group-2), using data from the national database (ITP registry) operated under the auspices of the Hellenic Society of Hematology. Methods: The Greek ITP registry recruits patients (n=1573) nationally through a network of 25 sites. In the present study, we retrospectively analyzed data from patients with primary and secondary ITP, aged over 18 years who were diagnosed from 1979 to 2022. Results: The number of evaluable patients was 580. Group-1 consisted of 464 (80%) and Group-2 of 116 (20%) patients. There were no differences in the median age, gender, the median platelet count or other hematological parameters between the 2 groups at diagnosis. Significantly fewer patients in Group-1 had comorbidities as compared to Group-2 (P=0.0206). Relevant medications were concurrently used at similar rates by the 2 patient groups. Bleeding manifestations were observed at a similar frequency between the 2 groups. Of those who were diagnosed as secondary ITP, 26.8% had infections, 24% had collagen disorders, 8.3% had Evans Syndrome, 5.5% had H.Pylori infection, 4.6% had Hashimoto thyroiditis and 3.6% antiphospholipid syndrome. In 3.7% of Group-2 patients ITP was drug-induced. Antiphospholipid antibody (Ab), platelet associated Ab, antinuclear Ab, HIV Ab and Rheumatoid Factor testing were performed more frequently in Group-2 patients. A significant higher proportion of Group-2 patients had a positive test for antinuclear antibodies, HCV Abs, antiphospholipid Abs and H.Pylori (P=0.0185, P=0.0004, P=0.0002 and P<0.0001, respectively). Fewer Group-1 patients received treatment at diagnosis (P=0.023). The choice of treatment at diagnosis did not differ between Group-1 and Group-2 patients with the exception of anti-CD20 which was administered more frequently in Group-1 patients (P=0.036). Overall response rates did not differ between the two groups. At 6 months post diagnosis significantly fewer Group-1 patients had bleeding manifestations and fewer Group-1 patients were treated with corticosteroids, IVIG, corticosteroids and IVIG and anti CD20 (P<0.0001, P=0.0144, P=0.0005 and P=0.039, respectively). At 6 months post diagnosis significantly fewer Group-1 patients had developed persistent ITP (p<0.005). Summary/Conclusion: The majority of adult Greek ITP patients suffered from primary ITP (Group-1). Secondary ITP (Group-2) was predominantly associated with collagen disorders and infections. Primary and secondary ITP patients did not differ in demographics, bleeding manifestations, and hematological parameters. However, patients with secondary ITP had a higher frequency of auto Abs. The form of ITP did not impact on the choice of initial treatment or the response rate but influenced the diagnostic work-up and the outcome of the disease, as suggested by the increased proportion of secondary ITP patients requiring treatment and developing persistent ITP at 6 months post diagnosis. Further investigation is warranted to probe more deeply into the differences and similarities of primary and secondary ITP in order to optimize management. Keywords: ITP, Immune thrombocytopenia (ITP)